a cruising concept for joy’n’ease, and a 9’ Walker Bay dingy

LT36 Cruising Sailboat, Blue Water Sailing, Design Competition 2003/04

LT36a cruising concept for joy’n’ease, and a 9’ Walker Bay dingy


LOA 36.2’LWL 34.5’Beam 11.6’Beam WL 9.9’Depth 9.2’Draft 4.8’Freeboard 4.4’Displacement 16.000 lbBallast 5.600 lb internal leadSail area 500 sqft main – 110 sqft alt. jib

SA/Disp 15.1LCB %WL 50.8VCB - 0.9’VCG - 2.6’Cb 0.37Cwp 0.65Disp/L 174

Hull speed 7.9 knBallast/Disp 35%Motion Comfort 26Screen number 1.87

Water 150 gallonsHolding tank 50 gallonsDiesel 150 gallons


The author’s intent has been to design a compact coastal cruiser with ease of handling and the capability to enter sheltered,shallow waters as well as being able for offshore crossings.It was more of a challenge to limit the size of the cruiser to a 36’, and thus more fun, than to go all the way to a 45 footer. Theself-imposed limitation was also put in place to investigate safe and comfortable single handling under all conditions, with asufficient vessel. A couple at sea is no less than single handling, most of the time.

In addition, to meet the requirementof the announced competition ofseaworthy storage and ease ofhandling the Walker Bay RID 9’dingy. It is stored on the centerline aftin it’s own bay. This allows foradditional usable deck space, as wellas providing a good place forsunbathing and play when moored.The dingy is launched and hoisted bytwo control lines on a single davit thatfollows the geometry of the biminicanopy structure. The arrangementprovides single-handed operation,and also safe boarding from thevessel to the dingy and vice versa. Italso doubles as a safety feature inMOB situations. Underway, the dingycan also be used as storage for allsorts of docking/playing/fishing/divinggear.The base concept is a 36’ mono-hullwith a collapsible A-framed lateen rigdesigned for low bridge clearances.The rig is unusual, but has beentested both in 1:10 RC scale, and on

a smaller vessel, and it points and drives quite well upwind. Due to the limited sail area, it will be outperformed by a sloopconfiguration down wind. Bridge clearance is 45 feet and the free board 3 feet amidships.

The deck plan doesn’t show the fore hatch, which is located at the fore end/top of the cabin trunk. The hatch should be largeenough to be usable for crew access to the foredeck.


The hull has a long waterline, and a fine entry with an elongated keel featuring a cut away forefoot and a deep vee for goodwave penetration to reduce slamming. The bow topsides are slightly hollow to shed the bow wave and reduce spray. The aft isflatter, and good hull balance and stability is maintained well up to a heel of 45 degrees and above. The short rig and the lowCg provide plenty of righting arm, and rigged with the lateen the hull heel noticeably less than the sloop, especially closehauled at 40 degrees to the wind. The lead provides a slight weather helm without the jib, and drives well upwind.

sail tests where the hull was tested and compared between an oversized 7/8 sloop and the A-frame/lateen. Scale 1:10. The hulls were vacuum formed inABS over a CNC routed MDF plug. Ballast was added to simulate full size ratios. The testing was based on timed GPS records of speed, VMG, winddirection and wind speed. The model test suggested the necessity of backstays as the rig moved forward and borrowed the bow on a run. The model hada self-tacking traveler on the foredeck. At full scale the author believes it would be beneficial to control the movement of the yardarm with controllines/blocks on the traveler.

The mast footings are placed above internal bulkheads to provide load distribution, stiffness, and to direct compression forcesto the keel. There is a fore traveler on the deck to receive the lower end of the yardarm. This feature controls the spar toreduce twist in the main, and point higher without excessive downwind drift. The traveler has a shock-absorbing car to receiveforward and down directed impacts from the yardarm.The hull is designed with thoughts on stability, roominess and is easily driven to hull speed. The keel has internal lead ballastand the rudder is hung on a skeg. The hull construction is solid S-glass with vinylester/epoxy. One could desire some Kevlarat the lead edges of hull/keel for impact resistance. Deck is cored with balsa and has a tanned non-skid surface. The sidedecks are wide and uncluttered. There is a 4 inch toe-rail all the way around. The bow pulpit provides safety, and also cradlesthe lead/storage for the anchor (CQR). The author has suggested a retractable bow spit for setting the jib alt. adrifter/asymmetrical spinnaker. The conflict with the ground tackle needs to be ironed out. Handrails, lifelines and portholesare not shown on the images.

The author has aimed for a simple, yet elegant little yacht with consequent lines and an easily driven, effective andcomfortable hull. The shallow draft allows for sheltered mooring and safe passages in inland waterways as well as coastalcruising.

Down below, the concept sleeps at least 6 people in 3 separate staterooms. The proposal represents a disposition of space,rather than surface qualities or practical details. With one exception; a large 2 cubic foot tray immediately inside and under thefirst step of the companionway to provide temporary, dry and sheltered storage from cockpit. Such is always in dire need.


There is a 6’3” headroom all the way up to the navstation. The author has emphasized privacy and rest in the below layout,and paid less attention to providing a large social area. That’s the job of the cockpit, and there will be a foldable table on thepedestal. The settee seats 4 in the L, and with an additional foldout on the end of the galley counter, and the stool for thenavstation, 6 folks can share a meal, or an anchor dram. The narrow pathway provides safety in a rough seaway. The galley isU-shaped and with ample counter space it should serve well both at sea and ported. No propane, an alcohol stove will do wellwith good port light ventilation. One might want to address the need for a longitudal pullout hip brace, maybe from the counter,when on a starboard tack. The galley and head was located so only one bulkhead is needed for plumbing with an eye on cost,weight and maintenance.There are two double staterooms aft on either side of the companionway with 7’ long, and 5’ wide bunks, then a galley to portand a L-shaped settee to starboard. Ahead to port is the head with a standup shower, head and a washbasin ( not detailed onthe ill.). To starboard ahead of the settee is full navstation with a 36x48 inch table and plenty of storage space. Up front aretwo sea berths on different levels and a sail locker. There is ample storage below the sea berths, under the settee, and in theaft staterooms. The aft staterooms both have hanging lockers. The shower stall doubles as wet locker.

The layout provides good visual contact between the helm, and the galley and navstation.


The engine is a 3 cylinder Yanmar, placed below the companionway with access from both sides through sliding doors in theaft staterooms, and if needed, by removing the companionway ladder. It became a design requirement to be able to work onthe engine without bringing the whole interior in disarray. The double bunks fold up to provide dirt/oil protection of thebeddings when accessing the engine compartment. The fold-up bunks are also intended to provide a stable bed in a roughseaway. The fold-ups are held in place by webbing to the ceiling.

The image shows an upside-down cut-away from below the waterline.From fore, the collision/buoyancy chamber, the chain locker in green, the ballast and the water/holding tanks (built-in), the engine (cyan) and the fuel tanksin yellow.

The engine is mainly below the waterline to contribute to stability and a low Cg. Batteries are located under the starboardsettee to counter balance the hull from the galley and head equipment. And to provide a fairly evenly distributed cablingscheme between the engine, the main panel by the navstation and equipment such as a windlass on the foredeck.There are two watertight, foam filled compartments, at the very fore and aft. The fore compartment, under the sail locker, islocated to reduce the risk of catastrophic flooding in case of collisions with floating objects at sea.Arrgh, those damn containers.The chain locker is aft and below this compartment, with the chain fed through a pvc pipe from deck; centered and loweredwith concerns for CG.


stations on 1’ c/c

buttocks on 0.5’ c/c

The hull has a slight tumblehome, and the decks are sloping transversely to shed water and to provide a steady footing whenhealed on a tack. There may be a form issue with the keel/hull geometry at the forefoot, but it’ll be taken care of.The author hopes the design investment in the hull will prove itself. Fair lines and easily driven as intended.


The cockpit is small, but will seat 4 people with ease. The size is driven by the dingy bay, but also to minimize potentialstability problems if flooded. The cockpit has two drains aft, which empties into the bay to reduce through hulls. The cockpitsole is at a 2 degree slope aft to assure rain drainage. The helm is compact and provides reach to the mainsheet, jib sheetsand running back stays, unless the helmsman has very short arms. The curved helm seat is partially above the dingy, andshould accommodate a variety of positions to easy a long watch. The dingy bay is open aft to provide immediate and ampledrain when flooded by following seas. There must be a canvas cover for the dingy for blue water sailing.Above the helm is a bimini canopy that receives the mainsheet and the back stays. The main is loose footed without a boom,but reinforced with full battens. The lower batten is double. The mainsheet car will run on a traveler at the front of the canopystructure. The foot of the main / mainsheet tackle is 6.5’ above the cockpit sole to avoid head banging accidents when gibed;accidental or not as they occur. Excess sheets and control lines can be coiled in the dingy to minimize clutter in the cockpit.The canopy also serves as a platform for navigational and communication antennas, lights, and as rest for the loweredyardarm when passing under low bridges. The canopy is oversized with 4 permanently brazed attachments to the deck. Thereare two large deck lockers for port lines, fenders etc, aft on top of the fuel tanks, on each side of the bay, - to avoid the usualmess and confusion in the cockpit during docking. The lockers also provide access to the aft of the hull, which is separatedfrom the living area by a watertight bulkhead. Aft of this bulkhead are the 2 diesel tanks and filters.The arrangement will hopefully minimize fuel odors in the living space.The companionway is traditional with a forward sliding hatch and 2 hatch boards in louvered, lexan and closed teak variantsaccording to needs. There is a full dodger or spray hood, which provides cover for the companionway hatch and shelter for thecrew. The spray hood cover is suggested in heavy transparent vinyl. The dodger folds forward, but also aft, to close off a smallspace outside the hatch for sheltered ventilation, and privacy during docking/mooring/bad weather.

The coamings are wide to provide good seating/stepping. The undercut on the deck side can be achieved with mold inserts,and possible flashing from the part lines, can be covered by the non-skid treatment. The two primary winches are reachedfrom both the helm and the cockpit.


The helm provides good outlook forward. The concept is developed with primary thoughts on safety, joy of sailing and ease ofhandling, for both crew and skipper. The bridge deck provides seating and safety from flooding the below, but the drawback isof course a tall companionway ladder.One has to think before one leaves the below, so one doesn’t forget what one was planning to bring out ;), and regret whatone left behind…oh boy

The prismatic coefficient indicates a hull with better performance downwind than beating into it. And that is intentional, ascruising is a tale of less resistance, but still; the hull will beat well against the wind and desire, but it will get you there.The marks represent CE for the main, and CLR.The rudder is hung on a skeg with a vertical rudderstock. The quadrant is driven by a chain link from the pedestal, and can bereached through the stateroom openings to the engine compartment.The rudder itself has more area at the foot so it will track well down wind, and thus avoid accidental broaching. The ruddersize is 12% of the lateral plane area. The prop is on a foldable two-blade 14” sail drive.


The spars are shown in carbon fiber. This may or may not be a preferred choice, but the question is rather to develop the rightgeometry for the A-frame. The flexibility of the rig and the resulting dynamic loads is a challenge under fire. And it is beingaddressed, both in theory and practice. The very concept contradicts the contemporary paradigm of demand for stiffness inthe rig, yet people have sailed the high seas for millenniums with very dynamic sail configurations. Without introducing astringent philosophical view, one could make a point in silence, by sailing the damn thing, as it moves.The author built and sailed this very rig configuration, as a kit for rental 16’ canoes with a bilge board and all the geometricvariants the rig and hulls demand. These particular spars were made of hollow, laminated Douglas fir and tads of white ash atthe stress points. And they worked well to develop knowledge and joy.

One could easily imagine a composite rig between synthetic fibers and wood; both for appearance, strength and ease ofrepair. There are a few details to be ironed out/shown with regards to the hoisting/movement, but the author is holding back onthis due to pending patents.The rig is shown with 2 reefing lines, and the battens are angled down forward to enable easy collapsing of the sail’s foot inreefing.

The rig is easy to operate, and it sails better than anticipated. That’s all I know.


The yardarm can easily be lowered, and the A-frame, by use of the running backstays, can also be lowered forward for easymaintenance, and low bridges.The yardarm is hoisted by a halyard, which runs through a sheave at the top center of the A-frame. The halyard is lead aft tothe cockpit so one can use the main winches, alternatively by using a combined windlass/winch on the foredeck. Either way,one avoids balancing the cabin trunk to hoist and strike the main.The main runs on batten cars, on the yardarm track. The author was contemplating a longitudal sail cradle on the cabin top,but abandoned the idea due to aesthetic concerns. It’s cluttered enough as it is. Let’s keep it simple.

Bridge clearance with the rig collapsed is less than 10 feet; the radar pole and antennas will have to come down though. Theauthor is working on that one.

The lowered yardarm will serve well, and could easily also be utilized as the backbone for a whole-hull awning in the tropics.Or for a week in rainy Maine or Pugent Sound, and at the same time reduce the windage when hooked in that very specialcove.


Fair winds and thanks for your attention.

a cruising concept for joy’n’ease, and a 9’ Walker Bay dingy

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